Manufacttoe of polymerized drying



5& 600 F. (230-315 C.).

Patented Apr. 18, 1939 MANUFACTURE OF PigLYMERIZED DRYING Eric IFawcett, Reginald Oswald Gibson, and Michael Willcox Perrin,

Winnington,

Northwich, England, assignors to Imperial Chemical Industries Limited, acorporation of Great Britain No {h Application February 5, 1936, Se-

rial No. 62,544. In Great Britain February 15,

6 Claims.

merized drying oils.

In the production of polymerized or bodied drying oils from drying oils,the latter are usual- 1y subjected to the action of heat, with orwithout catalysts and with or without the action of air or oxygen. Theproducts-are technically known as stand oils or as blown oils and havemany uses, notably for the preparation of paints, varnishes, printinginks and the like.

A process is also known for the production of w synthetic polymerizeddrying oils; which coniprises the steps of saponifying and acidifyingthe initial drying oil (e. g. linseed oil), subjecting the fatty acidsso obtained to the action of heat at ordinary pressure to eiiect theheat polymerization of the fatty acids (an action like that in makingstand oils), distilling away (suitably in vacuo) the monomeric from thepolymeric acids, and esterifying the latter to produce the requireddrying oil from the poly- Bd merized acids.

Heat polymerization, whether of drying oils or of drying oil fattyacids, necessitates a fairly high temperature (such as 280 C. or over)and a fairly long period of heating-two factors which to influence theproperties of the products obtained.

The application of heat to most vegetable and some animal oils causes athickening or polymerization of the oil. cause polymerization usuallylie between 450- At higher temperatures condensation takes place muchfaster but this at a sacrifice of color or formation of high acid value.The degree of polymerization is a direct coeflicient of temperature andtime, the only ex- {0 ception in this-case being China-wood oil whichsuddenly becomes solid at a temperature above 500 F. The customaryheating time is 5 to 7 hours. In the case of linseed oil, polymerizationbegins when the oil is heated to about 200 C.

5 We have now found that by eiiecting the heat polymerization of dryingoils or of drying oil fatty acids under very high pressure, namely apressure of above about 500 atmospheres, polymerized oils of improvedproperties are obtained 0 from the drying oils, while polymerized dryingoil fatty acids capable, when worked -up by known methods, of yieldingsynthetic polymerized drying oils of improved properties, are obtainedfrom the drying oil fatty acids. The 5 improved properties referred toare improved Temperatures which will with respect to the properties ofthe corresponding materials prepared by heat polymerization at lowpressures.

According to the present invention, therefore, we produce polymerizeddrying oils or polymerized drying oil fatty acids by subjecting dryingoils or drying oil fatty acids as the case may be, or materialscontaining the same, to the action of heat and of very high pressure, ofat least about 500 atmospheres, for a sufiicient period of time toefiect substantial polymerization of the drying oils or drying oil fattyacids.

Suitable drying oils which may be treated by the invention are linseedoil, perilla oil, soya bean oil and the like, also certain fish'oils,more especially those which have an iodine value above about 120, which,although not commonly classed as drying oils, arev polymerizable and canbe converted into polymerized oils adapted. for use as paint or varnishingredients.

The term drying oil used herein means any oil which can be polymerizedby heat and pres sure to yield a product like stand oil, suitable foruse'as an ingredient for paints, varnishes, printing inks and the like.

The drying oil fatty acids employed according to the invention may besynthetic or natural materials. They may suitably be obtained in knownmanner by saponification of the drying oils and acidification of theproducts. The,initial material, i. e., drying oils or drying oilfattyacids, may be subjected to a preliminary de-gassing treatment priorto polymerization so as to remove any dissolved oxygen or any water thatmay be present, these impurities being liable to cause undesireddecomposition during the .polymerization.

The ploymerization may be carried out as a batchprocess or as acontinuous process; in the pressed to the required high pressure andpassed through a heated tube, at the exit end of which is a valveregulating the through-put in accordance with the required reactiontime, which may be chosen to give, say, a product of a certainviscosity.

The products from the polymerization may, with the object of effecting astill further improvement in their properties, be subjected toshort-path high-vacuum distillation, mainly with the objects 01'.distilling away unpolymerized material from the desired polymerizedmaterial and 01 removing any undesired decomposition products which mayhave formed during the polymerization stage.

B a short-path high-vacuumdistillation is meant a distillation under avery high. vacuum of the order of 10- to 10- mm. of mercury, andunderconditions such that the distilling and conaisaooo polymerization oflinseed oil at 260 C., the criterion chosen being the Viscosity of thestand oil. The results are shown in the following table:

sirable dark brown colour. Example 3 This example shows the effect ofdifierent high pressures and times of treatment on the heat ing theresidue of said distillation to produce a polymerized drying oil.

3. The process of polymerizing linseed oil which comprises subjectingsaid oil to the action of a temperature of about 325 C. and of apresdensing surfaces are in close proximity, usually Pressure (ab Timeviscosity 5 about 1-5 cm. apart. o p nutes) (n The following examplesare given to illustrate how the invention may be carried out and 2, 30am the nature of the products obtained. The inveng'ggg g3 tion is not,however, limited to the materials and 61 60 1 n conditions described inthe examples. g 1% Example 1 3 2 An alkali-refined linseed oil, havingan iodine 1 N value of 183.6 and an acid number of 0.09, was heated at325 C. under a pressure of 3000 at- Ewmple 4 mospheres, for 1 hours. Theprodu had A sample of soya bean oil was polymerized by viscosity oi 103poises, an iodine value of 12 heating for 70 minutes at 325 C. under apresa d anac d Value Of t s colour was ra sure of 3000 atmospheres. Theproduct was sublighter than that of e a jected to short-path high-vacuumdistillation. so

For comparison, another sample of the original varnishes were made, in amanner Similar to that Oil was heated under atmosphenc pressuredescribed in connection with Example 1, from the for 11/2 the Pmduct hadviscoslW residue from the distillation, also from the resici 7 pulses,an iodine value of 127.6, and a acld due from the short-path high-vacuumdistillation Value I of a sample of soya bean oil which had beenpolyvarnishes were made from the above two prod merized (to about thesame viscosity). at atmosucts and from a commercial stand oil (having apheric pressure The drying times of the two viscosity of 95 poises) andthe drying times comvarnishes were as follows; pared. In carrying outthe tests, the oils, with the addition of 0.1 per cent by weight ofcobalt D h m (added as the linoleate) were thinned with turp'entine toaviscosity of about 3 poises, and the Vflmmh made f gfig g f varnish wasallowed to stand for 24 hours and ggi Hardset then flowed on to glasspanels.

High pressure polymerized oil 4% 8% Drying time in hours Low pressurepolymerized oil 6% Over 26 vamsh mademm sui-reoe Hard set Tack free Inthe examples the temperatures are all poly- Set merizing temperatures asconventionally understood in the art. 40 Linseed oil heated to 325? C.for 5% Over lO Not after Variou modifi atio of th terial a d r 53 153 atatmospheric 24 hours cedure previously described may be made in car-Oommercialstand 011 0W1) 32 g rying out our invention, and all suchmodifica- Linseed oil heated to 325 c. for on 1 Tack lree tions are'mtended to come within t scope of l gg u gg pressure 0! fig 24 theappended claims in so far as they achieve to L a useful degree the newresults, improvements and advantages hereinbefore described. "fixamme 2We claim:

Fatty acids obtained from linseed oil in known 1. The process ofconverting drying oil fatty manner, by saponifying the crude linseed oilwith acids into a polymerized drying oil, which comso caustic sodasolution, followed by acidification prises polymerizing such acids bysubjecting them with sulphuric acid, were heated at 280 C. under to theaction of heat at a temperature of at least a pressure of 3000atmospheres for 3 to 4 hours. approximately 260 0., and of a pressure ofat The product was substantially colourless, or of least about 500atmospheres, for a time sumcient comparatively light colour, andconsisted of a to efiect substantial polymerization of the fatty 5!mixture of polymerized and monomeric fatty acids, recovering theresulting polymerized dry-g acids. The latter were removed bydistillation ing oil fatty acids and esterifying them to proin vacuo (e.g. by short-path high-vacuum distilduce a polymerized drying oil.lation) and the polymeric acids were esterified, 2. The process ofconverting drying oil fatty yielding a polymerized drying oil which wasalso acids into a polymerized oil which comprises 6t substantiallycolourless or comparatively lightpolymerizing such acids by subjectingthem to the coloured. action of heat at a temperature of at least ap-FOr BOmPaIiSOII, P ymerization of another proximately 260 C., and of apressure of at least Sample f the fatty acids was efiected under theabout 500 atmospheres, for a time sufiicient to usual conditiops, W tthe application of presr effect substantial polymerization of the fattyf A tlme of 1245 hours was acids, submitting the resulting product toshortqmred to effect the Same degree of polymenza" path high-vacuumdistillation to remove unde- .325 22 3 2 i g gg f g g g g ggfi g 3gsired materials such as unpolymerizedacid and pared therefrom byesterification had an unde decomposition products therefrom, andesterify- 7 sure of about 3000 atmospheres for a period of about 1 /2hours.

4. The process of polymerizing linseed oil fatty acids which comprisessubjecting said acids to the action of a temperature of about 280 C. andof a pressure of about 3000 atmospheres for a period of about 3 to 4hours.

5. The process of polymerizing soya bean oil which comprises subjectingsaid oil to the action of a temperature of about 325 C. and of apressure of about 3000 atmospheres for a period of about 70 minutes.

6. A process of producing improved polymerized drying oils whichcomprises subjecting a substance. selected from the class consisting oflinseed oil, perilla oil, soya bean oil and fish oils having an iodinevalue above 120, and the corresponding drying oil fatty acids, to apressure of 3000 to 12,000 atmospheres at a temperature or 260 to 325 C.for a period of time, not over four hours, cient to achieve the requireddegree of polymerization.

